Computationally-efficient stochastic cluster dynamics method for modeling damage accumulation in irradiated materials

JOURNAL OF COMPUTATIONAL PHYSICS

卷:300

Article

Hoang, Tuan L.^1,2  Marian, Jaime^2,3  Bulatov, Vasily V.²  Hosemann, Peter¹ 

[1] Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA

[2] Lawrence Livermore Natl Lab, Phys & Life Sci Directorate, Livermore, CA 94550 USA

[3] Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 94720 USA

关键词: Stochastic cluster dynamics;    Irradiation damage;    Stochastic simulation algorithm;    Tau-leaping;   

DOI  :  10.1016/j.jcp.2015.07.061

来源: Elsevier

【 摘 要 】

An improved version of a recently developed stochastic cluster dynamics (SCD) method (Marian and Bulatov, 2012) [6] is introduced as an alternative to rate theory (RT) methods for solving coupled ordinary differential equation (ODE) systems for irradiation damage simulations. SCD circumvents by design the curse of dimensionality of the variable space that renders traditional ODE-based RT approaches inefficient when handling complex defect population comprised of multiple (more than two) defect species. Several improvements introduced here enable efficient and accurate simulations of irradiated materials up to realistic (high) damage doses characteristic of next-generation nuclear systems. The first improvement is a procedure for efficiently updating the defect reaction-network and event selection in the context of a dynamically expanding reaction-network. Next is a novel implementation of the tau-leaping method that speeds up SCD simulations by advancing the state of the reaction network in large time increments when appropriate. Lastly, a volume rescaling procedure is introduced to control the computational complexity of the expanding reaction-network through occasional reductions of the defect population while maintaining accurate statistics. The enhanced SCD method is then applied to model defect cluster accumulation in iron thin films subjected to triple ion-beam (Fe3+, He+ and H+) irradiations, for which standard RT or spatially-resolved kinetic Monte Carlo simulations are prohibitively expensive. (C) 2015 Elsevier Inc. All rights reserved.

【 授权许可】

Free